Methods and apparatus for treating glaucoma

ABSTRACT

An ocular implant for treating glaucoma is provided, which may include any number of features. More particularly, the present invention relates to implants that facilitate the transfer of fluid from within one area of the eye to another area of the eye. One feature of the implant is that it includes a proximal inlet portion and a distal inlet portion adapted to be inserted into the anterior chamber of the eye, and an intermediate portion adapted to be inserted into Schlemm&#39;s canal. Another feature of the implant is that it can be biased to assume a predetermined shape to aid in placement within the eye.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/968,051, filed Aug. 15, 2013, which application is a divisional ofU.S. application Ser. No. 13/610,769, filed Sep. 11, 2012, now U.S. Pat.No. 8,529,494; which application is a continuation of U.S. applicationSer. No. 12/398,847, filed Mar. 5, 2009, now U.S. Pat. No. 8,267,882;which application claims the benefit under 35 U.S.C. 119 of U.S.Provisional Patent Application No. 61/034,059, filed Mar. 5, 2008,titled “METHODS AND APPARATUS FOR TREATING GLAUCOMA.” These applicationsare herein incorporated by reference.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD

The present invention relates generally to devices that are implantedwithin the eye. More particularly, the present invention relates todevices that facilitate the transfer of fluid from within one area ofthe eye to another area of the eye.

BACKGROUND

According to a draft report by The National Eye Institute (NEI) at TheUnited States National Institutes of Health (NIH), glaucoma is now theleading cause of irreversible blindness worldwide and the second leadingcause of blindness, behind cataract, in the world. Thus, the NEI draftreport concludes, “it is critical that significant emphasis andresources continue to be devoted to determining the pathophysiology andmanagement of this disease.” Glaucoma researchers have found a strongcorrelation between high intraocular pressure and glaucoma. For thisreason, eye care professionals routinely screen patients for glaucoma bymeasuring intraocular pressure using a device known as a tonometer. Manymodern tonometers make this measurement by blowing a sudden puff of airagainst the outer surface of the eye.

The eye can be conceptualized as a ball filled with fluid. There are twotypes of fluid inside the eye. The cavity behind the lens is filled witha viscous fluid known as vitreous humor. The cavities in front of thelens are filled with a fluid know as aqueous humor. Whenever a personviews an object, he or she is viewing that object through both thevitreous humor and the aqueous humor.

Whenever a person views an object, he or she is also viewing that objectthrough the cornea and the lens of the eye. In order to be transparent,the cornea and the lens can include no blood vessels. Accordingly, noblood flows through the cornea and the lens to provide nutrition tothese tissues and to remove wastes from these tissues. Instead, thesefunctions are performed by the aqueous humor. A continuous flow ofaqueous humor through the eye provides nutrition to portions of the eye(e.g., the cornea and the lens) that have no blood vessels. This flow ofaqueous humor also removes waste from these tissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of theanterior chamber of the eye through the trabecular meshwork and intoSchlemm's canal as new aqueous humor is secreted by the epithelial cellsof the ciliary body. This excess aqueous humor enters the venous bloodstream from Schlemm's canal and is carried along with the venous bloodleaving the eye.

When the natural drainage mechanisms of the eye stop functioningproperly, the pressure inside the eye begins to rise. Researchers havetheorized prolonged exposure to high intraocular pressure causes damageto the optic nerve that transmits sensory information from the eye tothe brain. This damage to the optic nerve results in loss of peripheralvision. As glaucoma progresses, more and more of the visual field islost until the patient is completely blind.

In addition to drug treatments, a variety of surgical treatments forglaucoma have been performed. For example, shunts were implanted todirect aqueous humor from the anterior chamber to the extraocular vein(Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,”Investigative Ophthalmology (February 1966)). Other early glaucomatreatment implants led from the anterior chamber to a sub-conjunctivalbleb (e.g., U.S. Pat. No. 4,968,296 and U.S. Pat. No. 5,180,362). Stillothers were shunts leading from the anterior chamber to a point justinside Schlemm's canal (Spiegel et al., “Schlemm's canal implant: a newmethod to lower intraocular pressure in patients with POAG?” OphthalmicSurgery and Lasers (June 1999); U.S. Pat. No. 6,450,984; U.S. Pat. No.6,450,984).

SUMMARY OF THE DISCLOSURE

The present invention relates to devices implanted within the eye. Inone embodiment, an ocular implant defines a generally cylindrical volumeand comprises a proximal inlet portion at a proximal end of the implant,a distal inlet portion at a distal end of the implant, the distal inletportion being biased to bend at a first radius of curvature, anintermediate portion positioned between the proximal inlet portion andthe distal inlet portion, and a plurality of openings in the implant tofacilitate fluidic flow laterally across the elongate implant. Theimplant can also define a lumen to facilitate fluidic flowlongitudinally along the implant.

In some embodiments, an intermediate portion of the implant is biased tobend at a second radius of curvature. In one embodiment, the firstradius of curvature is smaller than the second radius of curvature. Inother embodiments, the second radius of curvature can approximate thecurvature of Schlemm's canal.

In one embodiment, the proximal portion of the implant is biased to bendat a third radius of curvature. The third radius of curvature can begenerally smaller than the second radius of curvature. In anotherembodiment, the third radius of curvature can be generally equal to thefirst radius of curvature.

In some embodiments, the plurality of openings in the implant extendover more than about 50% of an outer surface area of the implant.

Yet another embodiment includes an ocular implant defining a generallycylindrical volume, comprising a proximal inlet portion at a proximalend of the implant, the proximal inlet portion adapted to be positionedin an anterior chamber of the eye, a distal inlet portion at a distalend of the implant, the distal inlet portion adapted to be positioned inthe anterior chamber of the eye, an intermediate portion positionedbetween the proximal and distal inlet portions, the intermediate portionadapted to be positioned in Schlemm's canal, and a plurality of openingsin the implant to facilitate fluidic flow laterally across the implant.The implant can also define a lumen to facilitate fluidic flowlongitudinally along the implant.

One embodiment includes an assembly, comprising an ocular implantdefining an implant lumen, a core disposed in the implant lumen, a guidewire disposed in a guide wire lumen defined by the core, wherein theguide wire is biased to assume a predetermined at rest shape, the guidewire having a distal radius of curvature and a proximal radius ofcurvature when the guide wire is assuming the predetermined at restshape, and wherein the proximal radius of curvature is greater than thedistal radius of curvature.

In one embodiment, the assembly further comprises a cannula disposedabout the ocular implant. In yet another embodiment, the assemblyfurther comprises a luer fitting disposed in fluid communication with alumen defined by the cannula.

In some embodiments, the proximal radius of curvature approximates thecurvature of Schlemm's canal. In other embodiments, an intermediateportion of the ocular implant is biased to bend at a second radius ofcurvature. In one embodiment, the proximal radius of curvature of theguide wire can be generally equal to the second radius of curvature ofthe ocular implant.

In other embodiments, the ocular implant and the core urge the guidewire to assume a stressed shape that is different from the predeterminedat rest shape. The stressed shape is generally straighter than thepredetermined at rest shape.

In some embodiments, the implant comprises a first material and the corecomprises a second material different from the first material. The firstmaterial and the second material typically comprise materials whichprovide a relatively low friction interface when placed in slidingcontact with one another. The first material and the second materialalso typically comprise materials which are unlikely to gall when placedin sliding contact with one another. In one embodiment, the firstmaterial comprises a metallic material and the second material comprisesa polymeric material.

In one embodiment, the guide wire comprises a first material and thecore comprises a second material different from the first material. Inanother embodiment, the first material and the second material comprisematerials which provide a relatively low friction interface when placedin sliding contact with one another. The first material and the secondmaterial typically comprise materials which are unlikely to gall whenplaced in sliding contact with one another. In one embodiment, the firstmaterial comprises a metallic material and the second material comprisesa polymeric material.

In another embodiment, a device comprises an ocular implant comprising abody and a hatch, the body defining a body lumen and a longitudinalaxis, the hatch defining a hatch lumen having a hatch axis, the hatchcomprising an arm hingedly connecting the hatch to the body, the hatchhaving a first position in which the hatch is generally coaxial with thebody, the hatch having a second position in which the hatch axis isskewed relative to the longitudinal axis of the body, and wherein thehatch is biased to assume the second position.

In one embodiment, the hatch is disposed in the first position, and thedevice further includes a core extending through the body lumen and thehatch lumen. In another embodiment, at least a portion of the hatchextends around a portion of the core across a radial span of more than180 degrees. In one embodiment, the core causes the hatch to remain inthe first position. In another embodiment, the hatch assumes the firstposition when the core is withdrawn from the hatch lumen.

Another embodiment of the invention includes an ocular implantcomprising a proximal locking portion at a proximal end of the implant,a distal locking portion at a distal end of the implant, an intermediateportion extending between the proximal locking portion and the distallocking portion, the intermediate portion having a longitudinal axisthat follows an arcuate path when the implant is assuming a relaxedshape, wherein the proximal locking portion is biased to extend in afirst radially inward direction relative to the arcuate path of thelongitudinal axis of the intermediate portion, and wherein the distallocking portion is biased to extend in a second radially inwarddirection relative to the arcuate path of the longitudinal axis of theintermediate portion.

In one embodiment, the first radially inward direction and the secondradially inward direction intersect one another. In another embodiment,the first radially inward direction and the second radially both leadout of Schlemm's canal of an eye when the intermediate portion of theimplant is disposed in Schlemm's canal of the eye.

In some embodiments, the implant is dimensioned so that the proximallocking portion and the distal locking portion will both extend througha wall of Schlemm's canal of an eye when the intermediate portion of theimplant is disposed in Schlemm's canal of the eye.

The implant described can reduce the likelihood that the intermediateportion of the implant will migrate within Schlemm's canal of an eyewhen the proximal locking portion and the distal locking portion bothextend through a wall of Schlemm's canal.

In some embodiments, the first radially inward direction and the secondradially both lead out of Schlemm's canal of an eye when thelongitudinal axis of the intermediate portion is coaxial with alongitudinal axis of Schlemm's canal. In another embodiment, a radius ofcurvature of the longitudinal axis of the intermediate portionapproximates the curvature of Schlemm's canal when the implant isassuming the relaxed shape.

In yet another embodiment, a wall of the implant defines a plurality ofopenings in the implant to facilitate fluidic flow laterally across theimplant. The implant can also define a lumen to facilitate fluidic flowlongitudinally along the implant.

In one embodiment of the invention, an ocular implant defining agenerally cylindrical volume comprises a proximal inlet portion at aproximal end of the implant, the proximal inlet portion adapted to bepositioned in an anterior chamber of the eye, a distal inlet portion ata distal end of the implant, the distal inlet portion adapted to bepositioned in a suprachoroidal space of the eye, an intermediate portionpositioned between the proximal and distal inlet portions, and aplurality of openings in the implant to facilitate fluidic flowlaterally across the implant. The plurality of openings in the implantcan also facilitate fluidic flow longitudinally along the implant.

The present invention also relates to a method of treating glaucoma inan eye of a patient, comprising positioning a proximal inlet portion ofan implant in an anterior chamber of the eye, positioning anintermediate portion of the implant in Schlemm's canal, positioning adistal inlet portion of the implant in the anterior chamber of the eye,allowing aqueous humor to flow from the anterior chamber through theimplant into Schlemm's canal.

The allowing step can further comprise allowing aqueous humor to flowfrom the anterior chamber into the proximal and distal inlet portions,through the intermediate portion, and into Schlemm's canal.

In one embodiment, aqueous humor flows into Schlemm's canal through aplurality of openings in the implant.

In another embodiment, the proximal inlet portion of the implant can bespaced approximately 60 to 180 degrees from the distal inlet portion.

In yet another embodiment, aqueous humor can flow longitudinally alongthe implant. Aqueous humor can also flow laterally across the implant.

Yet another method of the present invention relates to a method ofimplanting a dual inlet ocular implant into an eye of a patient,comprising, inserting a cannula into an anterior chamber of the eye sothat a distal tip of the cannula is in communication with Schlemm'scanal, inserting a distal inlet portion of the implant through thecannula into Schlemm's canal, advancing the implant distally alongSchlemm's canal until only a proximal inlet portion of the implantremains in the cannula, introducing the distal inlet portion of theimplant into the anterior chamber of the eye from Schlemm's canal.

In one embodiment, the method further comprises removing the cannulafrom the anterior chamber of the eye leaving the proximal inlet portionof the implant in the anterior chamber of the eye.

In another embodiment, the introducing step comprises, advancing atissue penetrating guide wire distally from the implant to penetrateinto the anterior chamber of the eye from Schlemm's canal, advancing theimplant over the guide wire to introduce the distal inlet portion of theimplant into the anterior chamber of the eye from Schlemm's canal.

In an alternative embodiment, the introducing step comprises, making anincision from the anterior chamber of the eye into Schlemm's canal at aposition near the distal inlet portion of the implant, allowing thedistal inlet portion of the implant to assume a predetermined at restshape which results in the distal inlet portion bending through theincision into the anterior chamber of the eye from Schlemm's canal.

In another embodiment, the proximal inlet portion is spacedapproximately 60 to 180 degrees from the distal inlet portion.

In one embodiment, the method comprises inserting a core into a lumendefined by the implant, and inserting a guide wire into a guide wirelumen defined by the core. Sometimes the core is disposed in the lumendefined by the implant while the implant is advanced distally alongSchlemm's canal. Other times the guide wire is disposed in the guidewire lumen defined by the core while the implant is advanced distallyalong Schlemm's canal.

In one embodiment, the introducing step comprises advancing a distalportion of the guide wire distally from the core to penetrate into theanterior chamber of the eye from Schlemm's canal, and advancing theimplant off of the core and over the guide wire to introduce the distalinlet portion of the implant into the anterior chamber of the eye fromSchlemm's canal.

In some embodiments, the distal portion of the guide wire is urged toassume a stressed shape when the distal portion of the guide wire isdisposed in the guidewire lumen and the distal portion of the guide wireis free to assume a predetermined at rest shape when the distal portionof the guide wire is advanced distally from the core.

In other embodiments, the distal portion of the guide wire has a distalradius of curvature when the distal portion of the guide wire is free toassume a predetermined at rest shape.

In yet other embodiments, a proximal portion of the guide wire has aproximal radius of curvature and the proximal radius of curvature isgenerally greater than the distal radius of curvature. In someembodiments the proximal radius of curvature approximates the curvatureof Schlemm's canal.

In some embodiments, the cannula can be flushed with a fluid. Theflushing can be performed prior inserting a distal end of the cannulainto the anterior chamber for preventing the introduction of air bubblesinto the anterior chamber of the eye.

In other embodiments, a bolus of viscoelastic material can be injectedproximate a target location in the anterior chamber of the eye. Themethod can further comprise piercing a wall of Schlemm's canal or atrabecular mesh with a distal end of the cannula at the target location.Alternatively, the bolus of viscoelastic material can be injected priorto piercing the wall of Schlemm's canal for precluding the formation ofa pool of blood near the target location.

In one embodiment, the introducing step comprises advancing aself-piercing distal inlet in a distal direction to cause the distalinlet to cut through Schlemm's canal into the anterior chamber. Theself-piercing distal inlet can be advanced while the distal inletportion is biased inwards.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic drawing of an ocular implant.

FIG. 2 is another drawing of the implant having a predetermined at restshape.

FIG. 3A is a drawing showing a delivery system for the ocular implant.

FIG. 3B is an enlarged view of a distal end of the implant mounted on acore.

FIG. 3C is an enlarged view of the distal end of the implant mounted ona core further illustrating a tissue piercing guide wire.

FIG. 4 is a simplified view showing a human face including a pair ofeyes.

FIG. 5 is an additional view of the eye shown in the FIG. 4 furtherillustrating a cannula inserted into the eye.

FIG. 6 is an enlarged view of the eye shown in FIG. 5 further showingthe cannula piercing the trabecular mesh and Schlemm's canal.

FIG. 7 is a further enlarged view of an eye further illustrating animplant partially inserted into Schlemm's canal.

FIG. 8A is an additional view of the eye shown in FIG. 7 furtherillustrating a guide wire penetrating the tissues of the eye into theanterior chamber.

FIG. 8B is a view of the eye shown in FIG. 7 further illustrating aproximal inlet of an implant in the anterior chamber and a distal inletof the implant in Schlemm's canal.

FIG. 8C is a view of the eye shown in FIG. 8B further illustratingmaking an incision near the distal inlet of the implant.

FIGS. 8D-8K are some embodiments of implants comprising a self-piercingdistal inlet.

FIG. 9 is a view of an eye with an implant having two inlets positionedin the anterior chamber and the remaining portion of the implantpositioned in Schlemm's canal.

FIG. 10 is a view of an ocular implant with a distal end positioned inthe suprachoroidal space of the eye.

FIG. 11 is another view of the ocular implant with a distal endpositioned in the suprachoroidal space of the eye.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are numberedidentically. The drawings, which are not necessarily to scale, depictexemplary embodiments and are not intended to limit the scope of theinvention. Examples of constructions, materials, dimensions, andmanufacturing processes are provided for selected elements. All otherelements employ that which is known to those of skill in the field ofthe invention. Those skilled in the art will recognize that many of theexamples provided have suitable alternatives that can be utilized.

FIG. 1 is a schematic view of an implant 100 that may be used, forexample, to facilitate the flow of aqueous humor within the eye of apatient. Implant 100 comprises spines 102 and 104 and a frame 106disposed between the spines. In FIG. 1, frame 106 comprises a firststrut 120 and a second strut 122. The struts extend between the spines.First strut 120 comprises a first edge 124A and a second edge 126A.Second strut 122 has a shape that is a mirror image of the shape of thefirst strut. Thus, the second strut comprises a first edge 124B and asecond edge 126B. In FIG. 1, a first opening 128 is defined by the spacebetween first edge 124A of first strut 120 and first edge 124B of secondstrut 122. Similarly, a second opening 130 is defined by the spacebetween second edge 126A of first strut 120 and second edge 126B ofsecond strut 122. The second opening generally divides the frame 106into a first strut and a second strut. The openings defined by implant100, such as first opening 128 and second opening 130, allow aqueoushumor to flow laterally across and/or laterally through the implant.

Implant 100 typically comprises a plurality of spines and a plurality offrames. These spines and frames are arranged in an “ABAB” pattern. Asshown in FIG. 1, implant 100 includes four spines and three frames,wherein each frame is positioned between adjacent spines. In otherembodiments, the implant can have more or fewer spines and framesdepending on the desired length and/or size of the implant. Implant 100can be shaped to have an outer surface 138 defining a generallycylindrical volume. An inner surface 140 of the implant defines anelongate channel 142 or lumen to facilitate fluidic flow longitudinallyalong the implant. The plurality of spines and plurality of frames canbe defined as an intermediate portion of the implant.

Implant 100 of FIG. 1 further comprises a proximal inlet portion 101Aand a distal inlet portion 101B. Each inlet portion includes a pluralityof apertures 105, to allow for fluid to flow into each inlet portion.The elongate channel 142 of implant 100 can fluidly communicate with thefirst and second inlet portions as well as first opening 128 and secondopening 130 of the implant. As shown in FIG. 1, the intermediate portionof the implant can be positioned between the proximal and distal inletportions.

Implant 100 may be inserted into Schlemm's canal of a human eye, forexample, to facilitate the flow of aqueous humor out of the anteriorchamber of the eye. Aqueous humor may flow, for example, into theproximal and distal inlet portions, through the intermediate portion ofthe implant, and into Schlemm's canal. Aqueous humor may exit Schlemm'scanal via natural outlets communicating with the canal. The flow ofaqueous humor may include axial flow along Schlemm's canal, flow fromthe anterior chamber into Schlemm's canal, flow leaving Schlemm's canalvia natural outlets communicating with the canal, and flow throughopenings in the implant. When in place within the eye, the implant cansupport trabecular mesh tissue and Schlemm's canal tissue and canprovide for improved communication between the anterior chamber andSchlemm's canal (via the trabecular meshwork) and between pockets orcompartments along Schlemm's canal. The implant can facilitate flow ofaqueous humor longitudinally along the implant, as well as laterallyacross the implant.

The outer diameter of the implant is selected to support the tissue ofSchlemm's canal without undue stretching and is typically in the rangeof 0.005 inches to 0.04 inches, and preferably in the range of 0.005inches to 0.02 inches. The arrangement of frames, spines, and openingsalong implant 100 support the tissue of Schlemm's canal with a minimumamount of material. In the embodiment shown in FIG. 1, for example, theopenings (such as openings 128 and 130) extend over more than 50% of atubular surface covering the volume of the portion of the implant lyingwithin Schlemm's canal. This combination of features helps aqueous humorflow between any pockets or compartments formed within Schlemm's canaland, therefore, between the anterior chamber of the eye and the outletsfrom Schlemm's canal to the venous system.

The implant 100 may be biased to assume a predetermined at rest shape.This predetermined shape may include one or more bends or curves alongthe length of the implant. The predetermined shape can generally modelthe anatomy of the human eye, and in particular, the anatomy ofSchlemm's canal into which it is to be implanted. FIG. 2 is a view ofimplant 100 assuming a predetermined at rest shape. As shown, theimplant has an at rest shape that is generally curved. This at restshape can be established, for example, using a heat-setting process. Theshape of the implant in FIG. 2 can include a distal radius of curvatureRA corresponding to each of the proximal and distal inlets 101A and101B, and an intermediate or proximal radius of curvature RBcorresponding to the intermediate portion of the implant between theinlets. The radius of curvature RB can approximate the curvature ofSchlemm's canal, for example. In the embodiment of FIG. 2, the distalradii of curvature RA are smaller than the intermediate radius ofcurvature RB. For example, the distal radii of curvature RA can beapproximately 0.105 inches and the intermediate radius of curvature RBcan be approximately 0.215 inches. In the exemplary embodiment of FIG.2, the distal radius of curvature RA corresponding to distal inlet 101Ais approximately the same as the distal radius of curvature RAcorresponding to inlet 101B. In some embodiments, however, the radius ofcurvature corresponding to distal inlet 101A can be different from theradius of curvature corresponding to inlet 101B.

As shown in FIG. 2, each of the proximal and distal inlets of theimplant follow a radius of curvature RA along an arc extending across anangle AA. Similarly, an intermediate portion of the implant (i.e., theportion of the implant disposed between the distal and proximal inlets)follows a radius of curvature RB along an arc extending across an angleAB. In one embodiment, angle AA can be approximately 0-45 degrees andangle AB can be between approximately 60-180 degrees.

Various fabrication techniques may be used to fabricate the implant. Forexample, implant 100 can be fabricated by providing a generally flatsheet of material and laser cutting the material. The material may thenbe formed into a generally tubular shape as shown in FIG. 1. Anyadjoining edges (such as edges 103) may be attached, such as by weldingor other techniques known in the art. In another embodiment, the implantmay be fabricated by providing a tube and laser cutting openings in thetube to form the shape shown in FIG. 1.

Implant 100 can be fabricated from various biocompatible materialspossessing the necessary structural and mechanical attributes. Bothmetallic and non-metallic materials may be suitable. Examples ofmetallic materials include stainless steel, tantalum, gold, titanium,and nickel-titanium alloys known in the art as Nitinol. Nitinol iscommercially available from Memry Technologies (Brookfield, Conn.), TiNiAlloy Company (San Leandro, Calif.), and Shape Memory Applications(Sunnyvale, Calif.).

The implant may include one or more therapeutic agents. One or moretherapeutic agents may, for example, be incorporated into a polymericcoating that is deposited onto the outer surfaces of the struts andspines of the ocular implant. The therapeutic agent may comprise, forexample, an anti-glaucoma drug. Examples of anti-glaucoma drugs includeprostaglandin analogs. Examples of prostaglandin analogs includelatanprost.

FIG. 3A is a partial view of a delivery system 300 used to deliver animplant 100 into the eye of a patient. The delivery system can comprisecore 302, a push tube 304, cannula 306, handle 308, and guide wire 314.In some embodiments, the delivery system may optionally include a fluidsource or syringe 310 in fluid communication with handle 308. In someexemplary methods, a syringe or other fluid source is used for flushingimplant 100 with fluid to remove air bubbles and prevent theintroduction of air bubbles into the anterior chamber of the eye. Insome additional exemplary methods, a syringe or other fluid source maybe used for injecting a viscoelastic into the eye for precluding theformation of a pool of blood near a target location.

Cannula 306 can be coupled to a distal end of handle 308. The cannulacan be relatively straight, or as shown in FIG. 3A, can have a curveddistal tip to aid in implanting implant 100 into an eye of a patient. Inthe embodiment of FIG. 3A, the distal end of cannula 306 is curved so asto pierce the trabecular mesh of a patient to gain access to Schlemm'scanal. It should be noted that in FIG. 3A, illustration of the distalend of cannula 306 has been enlarged for ease of visualization anddescription.

Delivery system 300 may also include a mechanism (not shown in FIG. 3A),such as a thumb wheel, lever, or button on or near the handle 308adapted to advance and retract core 302, push tube 304, and/or guidewire 314. This mechanism may also be used to retract core 302 relativeto push tube 304 and/or guide wire 314. The implant may be moved indistal and proximal directions by moving core 302 and push tube 304 withthe mechanism.

As shown in FIG. 3B, implant 100 can be mounted on core 302. Core 302can extend through a lumen defined by a push tube to extend throughimplant 100. In a preferred embodiment, core 302 extends beyond thedistal end of the implant with a tapered finish. In another embodiment,the core extends only to the distal end of the implant. In a preferredembodiment, core 302 comprises polymeric tubing. In other embodiments,core 302 can be fabricated from similar materials to that of theimplant, as described above. In general, the implant and core willcomprise materials which provide a relatively low friction interfacewhen placed in sliding contact with one another. Additionally, thematerials are unlike to gall when placed in sliding contact with oneanother.

Among other features, one particular function of core 302 is to blockthe openings formed in implant 100 so as to minimize interferencebetween the implant and tissue within Schlemm's canal as the implant isadvanced during implantation. With reference to FIGS. 3A-3B, it can beseen that core 302 substantially fills implant 100. Together, core 302and implant 100 form an assembly that presents a relatively smooth outersurface.

Another function of core 302 is to aid in the insertion of implant 100into the eye of a patient. FIG. 3B shows a close up view of the distaltip of core 302 with implant 100 mounted on the core. As shown in FIG.3B, the distal tip of core 302 is tapered and includes a guide wirelumen 312 which runs along the length of the core. The core can also bebiased to assume a predetermined at rest shape corresponding to thepredetermined shape of the implant 100 or any other desiredpredetermined shape. For example, an intermediate portion of core 302can be biased to curve at a radius of curvature RB, which corresponds toradius of curvature RB of the intermediate portion of the implant inFIG. 2 as described above. Similarly, a distal or proximal portion ofthe core can be biased to curve at a radius of curvature RA, whichcorresponds to radius of curvature RA of the distal and proximal inletportions of the implant. Despite the biased at rest shape of core 302,the core can be flexible enough to assume a generally straightenedconfiguration when inserted into a delivery system or cannula forimplantation into a patient, for example. If the core is biased toassume a predetermined at rest shape, then a portion of the core may beurged to assume a stressed shape when it is disposed in the implant.

FIG. 3C shows a close-up view of implant 100 mounted on core 302 andfurther including tissue piercing guide wire 314 adapted to advance andretract through the guide wire lumen of the core and extend out beyondthe core. The guide wire can also include a tissue penetrating tip toallow the guide wire to cut through and penetrate tissue when desired.The guide wire can be a metallic wire, such as stainless steel, nitinol,MP-35N alloy or other appropriate materials. In one embodiment, theguide wire can have an approximate diameter of 0.004 inches. In general,the guide wire and core will comprise materials which provide arelatively low friction interface when placed in sliding contact withone another. Additionally, the materials are unlike to gall when placedin sliding contact with one another.

The distal end of guide wire 314 can also be biased to assume apredetermined at rest shape or curvature corresponding to the at restshape of implant 100 or another desired at rest shape. For example, thedistal tip of guide wire 314 can be biased to curve at a radius ofcurvature RA, which corresponds to radius of curvature RA of the distaland proximal inlet portions of the implant as shown in FIG. 2, and anintermediate portion of the guide wire can be biased to curve at aradius of curvature RB, which corresponds to radius of curvature RB ofthe intermediate portion of the implant, as described above. The radiusof curvature RA can be smaller than the radius of curvature RB. Inanother embodiment, only the distal end of the guide wire can be biasedto assume a predetermined at rest shape or curvature. Despite the biasedat rest shape of guide wire 314, the guide wire is relatively flexibleand can assume a generally straightened or slightly curved configurationwhen inserted into guide wire lumen 312 of core 302, for example. Thiscould cause a portion of the guide wire to be urged to assume a stressedshape when it is disposed in the core, such as when a distal portion ofthe guide wire is disposed in an intermediate portion of the core, andcause the portion of the guide wire to assume the predetermined at restshape when it is advanced distally from the core, such as when thedistal portion is advanced distally from the core, for example. Thestressed shape is generally straighter than the predetermined at restshape. It should be noted that the guide wire can be correctly orientedrelative to the anterior chamber because the predetermined shape of theguide wire can self align to Schlemm's canal creating an automaticalignment of the distal radius of curvature of the guide wire.

In some useful embodiments, the relaxed shape of the guide wire isselected so that so that a distal portion of the guide wire extends intothe anterior chamber when a longitudinal axis of the proximal portion ofthe guide wire is generally coaxial with a longitudinal axis ofSchlemm's canal and the distal radius of curvature of the guide wire isfree to assume its relaxed shape. The guide wire tends to orient itselfwithin the core so that a plane defined by a longitudinal axis of theguide wire is coplanar with a plane defined by the longitudinal axis ofSchlemm's canal.

A method of implanting implant 100 into a patient will now be describedwith reference to FIGS. 4-9. The implant described herein is adapted tobe implanted into a patient's eye so that both the distal and proximalinlets are positioned in the anterior chamber of the eye while theremaining portion of the implant is positioned in Schlemm's canal. Thisfacilitates the flow of aqueous humor out of the anterior chamber of theeye through both inlets into Schlemm's canal, and then out of Schlemm'scanal via natural outlets communicating with the canal. An implant asdescribed herein advantageously provides for multiple fluid inlets,allowing the implant to facilitate flow of aqueous humor into Schlemm'scanal even if one of the inlets fails to function or becomes clogged.

FIG. 4 is a simplified drawing showing a human face including an eye 40.In FIG. 4, a surgeon can use a scalpel or knife 402 to make an incision404 through the cornea of the eye. FIG. 5 is an additional view of theeye shown in the previous figure. In FIG. 5, the distal tip of cannula306 can be inserted through the incision in the cornea.

FIG. 6 is a further enlarged view of eye 40. In FIG. 6, the distal tipof cannula 306 has pierced through trabecular mesh 50 and through thewall of Schlemm's canal 60. When the distal tip of cannula 306 piercesthrough these tissues, it places Schlemm's canal in fluid communicationwith the anterior chamber 70 of eye 40. As shown, the distal tip ofcannula 306 can be curved to achieve tangential entry into Schlemm'scanal. However, in other embodiments the cannula can be relativelystraight.

When the distal tip of the cannula pierces the tissues separatingSchlemm's canal from the anterior chamber, a small amount of blood mayflow from the venous system into Schlemm's canal. This blood willtypically cause Schlemm's canal to turn a red/pink color which canenhance the visibility of Schlemm's canal for a short time (i.e., untilthe blood in Schlemm's canal dissipates). It may be desirable to advancean implant into Schlemm's canal while the presence of blood in the canalis enhancing the visibility of the canal.

In some cases, however, blood will leak out of the puncture made by thedistal end of the cannula. When this is the case, the blood may poolaround the opening of the puncture and interfere with the physician'sability to see the opening. Methods described herein may be used todisplace any blood that is pooled around the opening of the puncture.Methods described herein may also be used to preclude blood from poolingaround the opening of a puncture.

Blood can be precluded from pooling near an anticipated puncture byinjecting a bolus of viscoelastic near the place where the puncture willbe made. Blood that has entered the anterior chamber may be displaced,for example, by injecting a bolus of viscoelastic near the place wherethe cannula has punctured the trabecular mesh. Various fluids may beused in conjunction with the methods described in this document.Examples of fluids that may be suitable in some applications includewater, saline, hyaluronic acid and/or viscoelastic. The term“viscoelastic” is sometimes used to describe various viscoelasticmaterials that are injected into the eye as part of a surgicalprocedure. Viscoelastics for use in ophthalmic surgery are commerciallyavailable from Bausch and Lomb Incorporated (Rochester, N.Y., U.S.A.)and Alcon, Incorporated (Hünenberg, Switzerland). Viscoelastics maycomprise, for example, hyaluronic acid. Hyaluronic acid is a materialthat is naturally found in the vitreous humor that fills the posteriorchamber of the eye. Accordingly, this material is well suited for use inophthalmic surgery. Hyaluronic acid is also known as hyaluronan andhyaluronate.

FIG. 7 is a further enlarged view of the eye shown in FIG. 6 with animplant partially inserted into the eye. During delivery, implant 100can be mounted on core 302 which is movable with implant 100, asdescribed above. Among other features, one particular function of core302 is to block the openings in implant 100 so as to minimizeinterference between the implant and tissue within Schlemm's canal asthe implant is advanced. As described above, distal inlet portion 101Bis situated at the distal end of implant 100, and core 302 extendsbeyond the distal inlet a small distance to a tapered finish. In apreferred embodiment, the entire length of the tapered end of core 302extends distally beyond implant 100. The tapered finish of the core canbe provided to facilitate dilation of tissue in Schlemm's canal whileminimizing the compressive forces necessary to advance the implant inthe canal.

A push tube can be engaged with a proximal end of implant 100. The pushtube may be used to apply distally directed force to the proximal end ofthe implant 100 to advance the implant into Schlemm's canal. Core 302can extend proximally into the push tube during implantation. A handheldactuator or mechanism (not shown) may be used to provide relative motionto the push tube, the core, and or the guide wire. When the implant isbeing inserted into Schlemm's canal, the tissue piercing guide wire canbe positioned within the guide wire lumen, but should not extend outbeyond the core to avoid cutting or penetrating tissue.

As shown in FIG. 7, the implant can be inserted into Schlemm's canalwith the push tube until the distal inlet portion 101B of implant 100 isin a desired position with respect to the proximal inlet or proximalportion of the implant. In FIG. 7, the distal inlet is positionedapproximately 180 degrees from the proximal inlet of the implant, whichat this point in the procedure is still positioned within cannula 306.In other embodiments, the distal inlet may be positioned at differentpositions with respect to the proximal inlet depending on the length ofthe implant, typically anywhere from 60 to 180 or more degrees apart.

At this point in the implantation procedure the distal inlet 101B can bere-inserted into the anterior chamber of the eye using one of severalmethods. A first method is illustrated in FIG. 8A. As shown in FIG. 8A,tissue piercing guide wire 314 can be extended distally from core 302.In some useful embodiments, the relaxed shape of the guide wire isselected so that so that a distal portion of the guide wire extends intothe anterior chamber when a longitudinal axis of the proximal portion ofthe guide wire is generally coaxial with a longitudinal axis ofSchlemm's canal and the distal radius of curvature of the guide wire isfree to assume its relaxed shape. The guide wire tends to orient itselfwithin the core so that a plane defined by a longitudinal axis of theguide wire is coplanar with a plane defined by the longitudinal axis ofSchlemm's canal.

As described above, the distal end of the guide wire 314 can have apre-biased radius of curvature RA, which can be smaller than the radiusof curvature RB of the portion of implant 100 within Schlemm's canal.Thus, when the guide wire is extended beyond the core, the guide wirewill be biased to curve inwards back into the anterior chamber of theeye. The tissue piercing distal tip of the guide wire can allow theguide wire to penetrate the tissues of Schlemm's canal and thetrabecular meshwork to gain access to the anterior chamber. Once accessto the anterior chamber has been achieved with the guide wire, theimplant and core can be advanced together over the guide wire toposition distal inlet 101B properly within the anterior chamber. Thetaper of the core will facilitate placement of the implant by dilatingan opening through the meshwork. The implant can then be advanced intothe anterior chamber and location can be achieved which allows bothinlets to extend equally and uniformly from the canal. Next, the guidewire 314 can be removed from the core 302, the core can be removed fromimplant 100, and cannula 306 can be removed from over the implant andout of the eye, leaving proximal inlet 101A and distal inlet 101B in theanterior chamber, and the remaining portion of implant 100 in Schlemm'scanal, as shown in FIG. 9.

When the proximal and distal inlets are positioned in the anteriorchamber, they effectively serve as anchors or locks to reduce thelikelihood that the intermediate portion of the implant will migrate ormove within Schlemm's canal or that the inlets will become dislodged orremoved from the anterior chamber. This is because the proximal anddistal inlets extend at a radially inward direction relative to thearcuate path of the longitudinal axis of the intermediate portion, whichcan be shaped to fit the contours of Schlemm's canal.

Other methods of inserting distal inlet 101B into the anterior chamberare illustrated in reference to FIGS. 8B and 8C. It should be noted thatthis method may be performed with or without the use of guide wire 314.If guide wire 314 is used, it can be removed from the core 302, the corecan be removed from implant 100, and cannula 306 can be removed fromover the implant and out of the eye, leaving proximal inlet portion 101Ain the anterior chamber, and distal inlet 101B and the remaining portionof implant 100 in Schlemm's canal. Removing the core from the implantcan cause the distal inlet to bias inwards to the predetermined at restshape, as described above. In some applications, the distal inlet maypush through the tissues of Schlemm's canal and the trebecular meshworkto enter the anterior chamber when the implant assumes its at restshape. In some cases, it may be desirable to make an incision in thetissues proximate the distal inlet. When this is the case, the incisionmay be made, for example, with a scalpel. In some embodiments, theimplant may include a cutter that is capable of making the incision. Inone embodiment, the distal inlet 101B can have a self-piercing distaltip. Advancing the self-piercing distal tip in a distal direction whenthe distal inlet is biased inwards can cause the distal inlet to cutthrough the tissues of Schlemm's canal and the trabecular meshwork togain entry into the anterior chamber.

In another embodiment, as shown in FIG. 8C, instead of having aself-piercing distal tip, a surgeon can make an incision near the distalinlet portion with scalpel 402. As described above, the portion ofimplant 100 near distal inlet 101B is biased to assume a predeterminedat rest shape or curvature with a radius of curvature RA, as shown inFIG. 2. Thus, when the incision is made near the distal inlet, thedistal portion of the implant comprising the distal inlet will bendinwards to assume the predetermined at rest shape, which results in thedistal inlet 101B positioning itself within the anterior chamber of theeye. As a result, the distal and proximal inlets will be positioned inthe anterior chamber of the eye, and the remaining portion of theimplant will be positioned in Schlemm's canal, as shown in FIG. 9. Inyet another embodiment, a surgeon can reach through the trabecularmeshwork to grab the implant with a surgical device, such as forceps, topull the implant from Schlemm's canal back into the anterior chamber.

Other embodiments of a self-piercing distal inlet are illustrated inFIGS. 8D-8K. FIG. 8D illustrates a distal inlet 101B with a cutter 802extending radially from the distal inlet. The cutter can be configuredto swing or “spring” outwards from hole 804, such as with a heat-set orshape-set design. For example, the cutter can be shape set with apredetermined body transition temperature which would cause the cutterto spring outwards from the hole when the implant is heated to thepredetermined body transition temperature. However, it should beunderstood that the cutter can be designed to swing outwards withoutrequiring the implant to be heated.

FIG. 8E is a top down view of distal inlet 101B further showing anotherview of cutter 802 and hole 804. In one embodiment, as shown in FIG. 8F,the cutter 802 can be tucked inside and held in place within the distalinlet when core 302 is inserted into the implant. Upon removal of thecore, the cutter can swing outwards into the position shown in FIG. 8D.

As shown in FIG. 8E, cutter 802 can be a triangular shape. Othervariations on the design can also be used, such as a serrated edgecutter 806, as shown in FIG. 8G, a rectangular cutter, a semicircularshaped cutter 808, as shown in FIG. 8H, or any other appropriatelyshaped cutter as long as the cutter is sharp enough to penetrate throughtissue. In the embodiment of a serrated cutter, the trabecular meshworkand Schlemm's canal can be cut by moving the implant back and forth toslice through tissue and introduce the implant into the anteriorchamber, for example.

FIGS. 8I-8K show an alternative embodiment of a self-piercing distalinlet having a hatch 810 that engages the core 302. The hatch comprisesan arm that hingedly connects the hatch to the implant. In FIG. 8I, whencore 302 is disposed within the implant, it engages hatch 810 to causethe hatch to be flush with the body of the implant, so that the hatch isgenerally coaxial with the implant. FIG. 8J illustrates a cross sectionof hatch 810 being flush with the implant while core 302 is disposed inthe implant. It can be seen that at least a portion of the hatch extendsaround a portion of the core across a radial span of more than 180degrees. When the core is removed from the implant, the hatch can beheat set or shape set to assume a predetermined shape, as shown in FIG.8K.

In FIG. 8K, hatch 810 is shown in a fully extended or “swung out”position due to removal of the core from the implant. This extendedposition causes the hatch to be skewed relative to the longitudinal axisof the implant. The hatch can be biased to assume this extendedposition, for example. The hatch can have a sharp tip or edge to slicethrough tissue, such as Schlemm's canal and/or the trabecular meshwork,to gain access to the anterior chamber of the eye.

In FIG. 10, a cannula 306 is shown extending through an incision 404 inthe cornea of an eye. In the embodiment of FIG. 10, an implant 100 hasbeen advanced into the eye so that a distal end of the implant isdisposed in the suprachoroidal space 1002 of the eye. FIG. 10 alsoincludes a view of sclera 90, ciliary body 92, and choroid 94 of theeye. The distal end of the implant can be distal inlet 101B, asdescribed above. In another embodiment, the distal end of the implantdoes not have to be distal inlet 101B, but rather can share the samestructural design as an intermediate portion of the implant, asdescribed above. A method associated with inserting implant 100 into thesuprachoroidal space 1002 of the eye can include the various deliverysystem components described herein, including core 302, cannula 306, andguide wire 314, for example.

FIG. 11 is an additional partial cross-sectional view of the eye shownin the previous figure. In the embodiment of FIG. 11, the cannula hasbeen withdrawn from anterior chamber 70 and incision 404 in the corneahas closed. Implant 100 is positioned so that its distal end is disposedin suprachoroidal space 1002 of the eye and the proximal end of implant100 is disposed in the anterior chamber. When this is the case, aqueoushumor can flow along the surface of implant 100. In this way, implant100 allows aqueous humor to leave anterior chamber 70 and entersuprachoroidal space 1002. Numerous veins and arteries are located insuprachoroidal space. Accordingly, aqueous humor entering thesuprachoroidal space can be absorbed into the bloodstream by passingthrough the walls of small blood vessels. This excess aqueous humor canthen be carried away be venous blood leaving the eye.

In the methods described above, the predetermined shape of the implant,core, and/or guide wire will typically self align the implant inSchlemm's canal. However, the implant may additionally be rotated withinSchlemm's canal to attain the appropriate orientation.

While exemplary embodiments of the present invention have been shown anddescribed, modifications may be made, and it is therefore intended inthe appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

What is claimed is:
 1. A method of facilitating movement of aqueoushumor from an anterior chamber into Schlemm's canal, the methodcomprising: supporting a first opening in trabecular mesh tissue and asecond opening in trabecular mesh tissue with an implant; flowingaqueous humor from the anterior chamber into a first inlet of theimplant into an elongate longitudinal open channel extending through thefirst opening into an intermediate portion of the implant disposed inSchlemm's canal; and flowing aqueous humor from the anterior chamberinto a second inlet of the implant and through the second opening intothe elongate longitudinal open channel in the intermediate portion. 2.The method of claim 1 further comprising flowing aqueous humor from theintermediate portion of the implant into natural outlets of the eyecommunicating with Schlemm's canal.
 3. The method of claim 2 furthercomprising flowing aqueous humor radially outward from the elongatelongitudinal open channel through a longitudinal opening in the implantinto the natural outlets.
 4. The method of claim 1 further comprisingflowing aqueous humor through the implant longitudinally along Schlemm'scanal.
 5. The method of claim 1 further comprising supporting Schlemm'scanal tissue with the intermediate portion of the implant.
 6. The methodof claim 1 wherein the first inlet is disposed at a first end of theimplant and the second inlet is disposed at a second end of the implant.7. The method of claim 6 wherein the implant is curved, the first inletbeing spaced 60 to 180 degrees from the second inlet.
 8. A method offacilitating movement of aqueous humor from an anterior chamber intoSchlemm's canal, the method comprising: supporting an opening intrabecular mesh tissue at a first location and a second location with animplant; flowing aqueous humor from the anterior chamber into a firstinlet disposed at a first end of the implant into an elongatelongitudinal channel extending through the first opening into anintermediate portion of the implant disposed in Schlemm's canal; andflowing aqueous humor from the anterior chamber into a second inlet ofthe implant disposed at a second end of the implant and through thesecond opening into the elongate longitudinal channel in theintermediate portion.
 9. The method of claim 8 further comprisingflowing aqueous humor from the intermediate portion of the implant intonatural outlets of the eye communicating with Schlemm's canal.
 10. Themethod of claim 9 further comprising flowing aqueous humor radiallyoutward from the elongate longitudinal open channel through alongitudinal opening in the implant into the natural outlets.
 11. Themethod of claim 8 further comprising flowing aqueous humor through theimplant longitudinally along Schlemm's canal.
 12. The method of claim 8further comprising supporting Schlemm's canal tissue with theintermediate portion of the implant.
 13. The method of claim 8 whereinthe implant is curved, the first inlet being spaced 60 to 180 degreesfrom the second inlet.